Jump to content

Virtual Jaguar and Atari workshop 'Illegal' exits...

Recommended Posts

Hi all, I've just been compiling some Atari Workshop stuff, part of Workshop series #1 - (My document is dated 8th Nov 1994 if its of interest)

Now, my problem isnt the compiling of code or even getting it to run. The problem I believe lies in the way the workshop code ends with 'Illegal', now reading a few other forums it seems that this was some magic way to use the alpine board.
The code runs but crashes on this piece of code.
Is there a way to create an infinite loop in ASM.

I did try the usual...

bra loop

but it seems Virtual Jaguar crashed using a loop like this on both versions I use...
v2.1.2 and
GIT 20160613

I have other samples that use 'ILLEGAL' to exit and these crash also, sometimes ending VJ abruptly or causing a non-responsive attitude ;)

If I could get it to loop at least Id be able to see how it works and how to create loops. Maybe there is some specific way as opposed to simply infinite looping lol. Im all VERY new to ths and have literally just got into Workshop #1
I know 'SOME' assembly but my forte is Atari ST coding.

Any help would be much appreciated, a stable loop with an OPL and VBL would help greatly tbh :)


  • Like 1
Link to comment
Share on other sites

Beside the object list refresh, you can also keep the illegal and set his vector #4 in accordance and do whatever you want (infinite loop in your case).


Vector #, Address, Exception name, Trigger condition

0, 000000, Reset SP, Not really a vector. Used to initialize the stack pointer.

1, 000004, Reset PC, Reset/startup

2, 000008, Bus error, Bus cycle couldn't complete properly.

3, 00000C, Address error, Misaligned (odd) word or longword memory access.

4, 000010, Illegal instruction, Tried executing an invalid opcode.

Edited by dilinger
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Create New...